She was in hospital and unable to attend the world premiere of the film at the Embassy Theatre last week.

Moran grew up in New York. She joined Weta Digital in 2001 and worked alongside Sir Peter on many of his movies, including The Lord of The Rings trilogy, The Lovely Bones and King Kong. She also worked on James Cameron's Avatar.

She was considered one of the movie industry's top visual effects producers.

In a note to Weta staff, Jackson and his partner, producer Fran Walsh, said they were ''terribly upset'' about Moran's death.

''Fran and I are terribly upset at the news that we lost Eileen a couple of hours ago,'' Sir Peter said.

''She was a lovely, decent person who had great respect for all the artists she worked with.

''Eileen was so proud of Weta and the work all of you have done over the years. She was fiercely loyal to the company, and to Fran and I personally, and we will always be grateful for her friendship.''

Moran was part of the Weta Digital team that won the best visual effects Oscar for Avatar in 2009.

Cameron told The Hollywood Reporter that she shepherded some of the milestone films of her generation to completion.

''Eileen was an integral part of building Weta Digital into the most powerful engine for imaginative imagery that ever existed.''

She is survived by her children, Jack and Ava.

A post on Tolkien fan site TheOneRing.net tonight extended deepest sympathies to her family, her loved ones, her friends and colleagues.